SCIENTIFIC RECREATIONS. 



during each rotation, as the armature approaches the magnets, it is attracted ; 

 but immediately afterwards, as the armature comes directly in front of the 

 magnets, the current is broken, and the acquired impulsion is sufficient to 

 move the wheel until the armature comes again under the influence of the 



magnet. The spring which interrupts the current is connected with a thin 

 copper wire, which stretches back as far as the point of the column, 

 entwining it several times to render it flexible, finally bending down and 

 plunging into some mercury enclosed in a round vulcanite cup placed on 

 the column near the pedestal. The pedestal also bears two small stakes 



